The present invention relates to Coryneform bacteria carrying a recombinant DNA molecules having inserted therein a gene coding for 3-deoxy-D-arabinoheptulonic acid-7-phosphate synthetase (hereafter referred to as "DS") and to processes for producing aromatic amino acids utilizing such bacteria.
DS is an enzyme which catalyses the synthesis of 3-deoxy-D-arabino-heptulonic acid-7-phosphate (hereafter referred to as "DAHP") from phosphoenolpyruvic acid and erythrose-4-phosphate. DAHP is converted into phenylalanine, tyrosine or tryptophan via chorismic acid. With respect to Coryneform bacteria, it is known that DS activity is synergistically inhibited by phenylalanine and tyrosine, which are final products. When breeding aromatic-amino-acid-producing bacteria, it is important to select a strain having potent DS activity, i.e., free from inhibition.
On the other hand, some processes for breeding aromatic-amino-acid-producing bacteria by recombinant DNA techniques are known (for example, Published Unexamined Japanese Patent Application Nos. 208994/82, 71397/82, 89194/83, 134994/83, etc.). In these processes, however, genes coding for DS of Coryneform bacteria (hereafter referred to as "DS gene") have not been inserted.